drivers/mfd/tps6594-spi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SPI access driver for TI TPS6594/TPS6593/LP8764 PMICs
   4  *
   5  * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/
   6  */
   7
   8 #include <linux/crc8.h>
   9 #include <linux/module.h>
  10 #include <linux/mod_devicetable.h>
  11 #include <linux/of_device.h>
  12 #include <linux/regmap.h>
  13 #include <linux/spi/spi.h>
  14
  15 #include <linux/mfd/tps6594.h>
  16
  17 #define TPS6594_SPI_PAGE_SHIFT  5
  18 #define TPS6594_SPI_READ_BIT    BIT(4)
  19
  20 static bool enable_crc;
  21 module_param(enable_crc, bool, 0444);
  22 MODULE_PARM_DESC(enable_crc, "Enable CRC feature for SPI interface");
  23
  24 DECLARE_CRC8_TABLE(tps6594_spi_crc_table);
  25
  26 static int tps6594_spi_reg_read(void *context, unsigned int reg, unsigned int *val)
  27 {
  28         struct spi_device *spi = context;
  29         struct tps6594 *tps = spi_get_drvdata(spi);
  30         u8 buf[4] = { 0 };
  31         size_t count_rx = 1;
  32         int ret;
  33
  34         buf[0] = reg;
  35         buf[1] = TPS6594_REG_TO_PAGE(reg) << TPS6594_SPI_PAGE_SHIFT | TPS6594_SPI_READ_BIT;
  36
  37         if (tps->use_crc)
  38                 count_rx++;
  39
  40         ret = spi_write_then_read(spi, buf, 2, buf + 2, count_rx);
  41         if (ret < 0)
  42                 return ret;
  43
  44         if (tps->use_crc && buf[3] != crc8(tps6594_spi_crc_table, buf, 3, CRC8_INIT_VALUE))
  45                 return -EIO;
  46
  47         *val = buf[2];
  48
  49         return 0;
  50 }
  51
  52 static int tps6594_spi_reg_write(void *context, unsigned int reg, unsigned int val)
  53 {
  54         struct spi_device *spi = context;
  55         struct tps6594 *tps = spi_get_drvdata(spi);
  56         u8 buf[4] = { 0 };
  57         size_t count = 3;
  58
  59         buf[0] = reg;
  60         buf[1] = TPS6594_REG_TO_PAGE(reg) << TPS6594_SPI_PAGE_SHIFT;
  61         buf[2] = val;
  62
  63         if (tps->use_crc)
  64                 buf[3] = crc8(tps6594_spi_crc_table, buf, count++, CRC8_INIT_VALUE);
  65
  66         return spi_write(spi, buf, count);
  67 }
  68
  69 static const struct regmap_config tps6594_spi_regmap_config = {
  70         .reg_bits = 16,
  71         .val_bits = 8,
  72         .max_register = TPS6594_REG_DWD_FAIL_CNT_REG,
  73         .volatile_reg = tps6594_is_volatile_reg,
  74         .reg_read = tps6594_spi_reg_read,
  75         .reg_write = tps6594_spi_reg_write,
  76         .use_single_read = true,
  77         .use_single_write = true,
  78 };
  79
  80 static const struct of_device_id tps6594_spi_of_match_table[] = {
  81         { .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, },
  82         { .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, },
  83         { .compatible = "ti,lp8764-q1",  .data = (void *)LP8764,  },
  84         {}
  85 };
  86 MODULE_DEVICE_TABLE(of, tps6594_spi_of_match_table);
  87
  88 static int tps6594_spi_probe(struct spi_device *spi)
  89 {
  90         struct device *dev = &spi->dev;
  91         struct tps6594 *tps;
  92         const struct of_device_id *match;
  93
  94         tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL);
  95         if (!tps)
  96                 return -ENOMEM;
  97
  98         spi_set_drvdata(spi, tps);
  99
 100         tps->dev = dev;
 101         tps->reg = spi->chip_select;
 102         tps->irq = spi->irq;
 103
 104         tps->regmap = devm_regmap_init(dev, NULL, spi, &tps6594_spi_regmap_config);
 105         if (IS_ERR(tps->regmap))
 106                 return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n");
 107
 108         match = of_match_device(tps6594_spi_of_match_table, dev);
 109         if (!match)
 110                 return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n");
 111         tps->chip_id = (unsigned long)match->data;
 112
 113         crc8_populate_msb(tps6594_spi_crc_table, TPS6594_CRC8_POLYNOMIAL);
 114
 115         return tps6594_device_init(tps, enable_crc);
 116 }
 117
 118 static struct spi_driver tps6594_spi_driver = {
 119         .driver = {
 120                 .name = "tps6594",
 121                 .of_match_table = tps6594_spi_of_match_table,
 122         },
 123         .probe = tps6594_spi_probe,
 124 };
 125 module_spi_driver(tps6594_spi_driver);
 126
 127 MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
 128 MODULE_DESCRIPTION("TPS6594 SPI Interface Driver");
 129 MODULE_LICENSE("GPL");